Vitamin D derivative having substituent at 2beta-position

ABSTRACT

A steroid intermediate has the formula (II):  
                 
 
     wherein A denotes alkylene of 2 to 10 carbons; X denotes halogen; R a , R b  and R c  denote, independently hydrogen or hydroxyl protecting group; and R p , R q , R y  and R z  are such that R p  and R q  together form a double bond between the 5-position and the 6-position and R y  and R z  together form a double bond between the 7-position and the 8-position, or R q  and R y  together form a double bond between the 6-position and the 7-position and R p  and R z  are bound to a dienophile capable of protecting conjugated double bonds.

TECHNICAL FIELD

[0001] This invention relates to a vitamin D derivative having asubstituent at the 2β-position. More particularly, the invention relatesto a vitamin D derivative having at the 2β-position an alkoxy groupsubstituted at the terminal position by SO₃R₁ wherein R₁ represents ahydrogen atom or a straight chain or branched chain alkyl group with 1to 3 carbon atoms or by COOR₂ wherein R₂ represents a hydrogen atom or astraight chain or branched chain alkyl group with 1 to 3 carbon atoms.

BACKGROUND ART

[0002] In recent years, vitamin D derivatives have been shown to havevarious physiological activities. One of vitamin D derivatives,1α,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃), is known to show wide varietiesof physiological activities, such as calcium metabolism regulatingactivity, activity of suppressing proliferation, or inducingdifferentiation, of tumor cells, etc., and immunomodulating activity.

[0003] However, 1α,25-dihydroxyvitamin D₃ is defective in that it maydevelop hypercalcemia, depending on its dose or its mode ofadministration. Using it, for example, as an antitumor agent or anantirheumatic agent poses difficulty. To separate these activities ofvitamin D, numerous vitamin D derivatives, such as 1α-hydroxyvitamin D₃,1α,24-dihydroxyvitaminD₃, 22-oxa-1α,25-dihydroxyvitaminD₃, and variousfluorinated vitamin D₃ products, have recently been synthesized, andtheir physiological activities are under investigation.

[0004] Of many vitamin D derivatives, known vitamin D₃ derivativeshaving substituents at the 2β-position include1α,25-dihydroxy-2β-fluorovitamin D₃ described in JapanesePatentPublication No. 1991-14303, vitamin D₃ derivatives having at the2β-position an amino group or a C₁₋₇ lower alkoxy group optionallysubstituted with a hydroxyl group, a halogen atom, a cyano group or anacylamino group (the derivatives described in Japanese PatentPublication No. 1994-23185), and vitamin D₃ derivatives having at the2β-position an optionally substituted lower alkyl, alkenyl or alkinylgroup which are described in Japanese Unexamined Patent Publication No.1994-41059. Some of these vitamin D₃ derivatives having substituents atthe 2β-position are known to have physiological activities, such as invivo calcium regulating activity, and activity of inducingdifferentiation of tumor cells, etc., and also known to be useful asdrugs, such as therapeutic agents for diseases due to disorder ofcalcium metabolism, such as osteoporosis or osteomalacia, or antitumoragents. Of these derivatives,2β-(3-hydroxypropoxy)-1α,25-dihydroxyvitamin D₃ is expected to be ofpractical use in treating osteoporosis, with a high blood level beingable to be maintained for a long duration.

[0005] As noted above, 2β-(3-hydroxypropoxy)-1α,25-dihydroxyvitamin D₃is under vigorous development as a useful drug, and its metabolites arealso under investigation. As studies of such metabolites of2β-(3-hydroxypropoxy)-1α,25-dihydroxyvitamin D₃ are under way, it hasbeen suggested recently that these metabolites appear to include thosein which the terminal position of the 3-hydroxypropoxy group at the2β-position has been converted to a carboxylic acid or a sulfonic acid.However, no reports have been issued on the synthesis of compounds inwhich the terminal position of the 3-hydroxypropoxy group at the2β-position of 2β-(3-hydroxypropoxy)-1α,25-dihydroxyvitamin D3 has beenconverted to a carboxylic acid or a sulfonic acid.

DISCLOSURE OF THE INVENTION

[0006] An object of the present invention is to provide a novel vitaminD derivative having at the 2β-position an alkoxy group substituted atthe terminal position by a sulfonic acid or a carboxylic acid or anester of any of these acids.

[0007] Another object of the invention is to provide a novel syntheticintermediate useful for synthesizing the novel vitamin D derivativehaving at the 2β-position an alkoxy group substituted at the terminalposition by a sulfonic acid or a carboxylic acid or an ester of any ofthese acids; specifically, a steroid compound having at the 2β-positionan alkoxy group substituted by a halogen atom at the terminal position.

[0008] Still another object of the invention is to provide a drugcontaining the above-mentioned vitamin D derivative according to theinvention as an active ingredient.

[0009] In an attempt to attain these objects, the inventor of thepresent invention used as a starting material a cholestane compoundhaving at the 2β-position an alkoxy group substituted by a hydroxylgroup at the terminal position, protected the hydroxyl groups and the5,7-diene portion that require protection, then converted the terminalhydroxyl group of the substituted alkoxy group at the 2β-position into anitrile and then into an ester, deprotected the conversion product, andthen performed light irradiation and thermal isomerization. By thisprocedure, the inventor succeeded in synthesizing the desired vitamin Dderivative having at the 2β-position an alkoxy group substituted by anester of a carboxylic acid at the terminal position. The inventor alsofound this vitamin D derivative to have affinity for a vitamin Dreceptor and a vitamin D-binding protein, and also to be useful as adrug. These achievements led to accomplishment of the present invention.

[0010] According to a first aspect of the invention, there is provided avitamin D derivative of the general formula (I):

[0011] wherein

[0012] A denotes a straight chain or branched chain alkylene group with2 to 10 carbon atoms; and

[0013] R denotes

[0014] SO₃R₁ in which R₁ represents a hydrogen atom or a straight chainor branched chain alkyl group with 1 to 3 carbon atoms or

[0015] COOR₂ in which R₂ represents a hydrogen atom or a straight chainor branched chain alkyl group with 1 to 3 carbon atoms.

[0016] In the general formula (I), A is preferably a straight chainalkylene group with 2 to 10 carbon atoms.

[0017] In the general formula (I), R is preferably COOR₂ wherein R₂represents a hydrogen atom or a straight chain or branched chain alkylgroup with 1 to 3 carbon atoms.

[0018] In the general formula (I), it is particularly preferred that Ais an ethane-1,2-diyl group, and R is COOR₂ wherein R₂ represents ahydrogen atom or a straight chain or branched chain alkyl group with 1to 3 carbon atoms.

[0019] Further preferred compounds as the vitamin D derivative of thegeneral formula (I) are2β-(2-carboxyethyloxy)-1α,3β,25-trihydroxycholesta-5,7-10(19)-triene and2β-(2-methoxycarbonylethyloxy)-1α,3β,25-trihydroxycholesta-5,7-10(19)-triene.

[0020] According to a second aspect of the invention, there is provideda steroid compound of the general formula (II):

[0021] wherein

[0022] A denotes a straight chain or branched chain alkylene group with2 to 10 carbon atoms;

[0023] X denotes a halogen atom;

[0024] R_(a), R_(b) and R_(c) denote, independently of each other, ahydrogen atom or a hydroxyl group protecting group; and

[0025] R_(p), R_(q), R_(y) and R_(z) are such that

[0026] R_(p) and R_(q) together form a double bond between the5-position and the 6-position and R_(y) and R_(z) together form a doublebond between the 7-position and the 8-position or

[0027] R_(q) and R_(y) together form a double bond between the6-position and the 7-position and R_(p) and R_(z) are bound to adienophile capable of protecting conjugated double bonds.

[0028] This compound is an intermediate compound useful for thesynthesis of the vitamin D derivative of the general formula (I).

[0029] In the general formula (II), it is preferred that A is a straightchain alkylene group with 2 to 10 carbon atoms, and X is an iodine atom.

[0030] According to a third aspect of the invention, there is provided apharmaceutical composition containing the vitamin D derivative of thegeneral formula (I) as an active ingredient (e.g., a therapeutic agentfor a disease due to a disorder of calcium metabolism).

PREFERRED MODES FOR CARRYING OUT THE INVENTION

[0031] In defining the vitamin D derivative of the general formula (I),examples of the straight chain or branched chain alkylene group with 2to 10 carbon atoms, as A, are straight chain alkylene groups which areethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl,hexane-1,6-dlyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl anddecane-1,10-diyl; and branched chain alkylene groups such as2-methylpropane-1,3-diyl, 2-methylbutane-1,4-diyl,3-methylbutane-1,4-diyl, 2,3-dimethylbutane-1,4-diyl2-methylpentane-1,5-diyl, 3-methylpentane-1,5-diyl,4-methylpentane-1,5-diyl, 2,3-dimethylpentane-1,5-diyl,2,4-dimethylpentane-1,5-diyl, 3,3-dimethylpentane-1,5-diyl,3,4-dimethylpentane-1,5-diyl, 2,3,4-trimethylpentane-1,5-diyl,3-ethylpentane-1,5-diyl, 3-ethyl-2-methylpentane-1,5-diyl,3-ethyl-4-methylpentane-1,5-diyl, 2,4-dimethyl-3-ethylpentane-1,5-diyl,2-methylhexane-1,6-diyl, 3-methylhexane-1,6-diyl,4-methylhexane-1,6-diyl, 5-methylhexane-1,6-diyl,2,3-dimethylhexane-1,6-diyl , 2,4-dimethylhexane-1,6-diyl, 2,5-dimethylhexane-1,6-diyl, 3,3-dimethylhexane-1,6-diyl,3,4-dimethylhexane-1,6-diyl, 3,5-dimethylhexane-1,6-diyl,4,4-dimethylhexane-1,6-diyl, 4,5-dimethylhexane-1,6-diyl,2,3,3-trimethylhexane-1,6-diyl, 2,3,4-trimethylhexane-1,6-diyl,2,3,5-trimethylhexane-1,6-diyl, 2,4,4-trimethylhexane-1,6-diyl,2,4,5-trimethylhexane-1,6-diyl, 3,3,4-trimethylhexane-1,6-diyl,3,3,5-trimethylhexane-1,6-diyl, 3,4,5-trimethylhexane-1,6-diyl,4,4,5-trimethylhexane-1,6-diyl, 2,3,4,5-tetramethylhexane-1,6-diyl,3-ethylhexane-1,6-diyl, 4-ethylhexane-1,6-diyl,3-ethyl-2-methylhexane-1,6-diyl, 3-ethyl-4-methylhexane-1,6-diyl,3-ethyl-5-methylhexane-1,6-diyl, 4-ethyl-2-methylhexane-1,6-diyl,4-ethyl-3-methylhexane-1,6-diyl, 4-ethyl-5-methylhexane-1,6-diyl,2,4-dimethyl-3-ethylhexane-1,6-diyl,2,5-dimethyl-3-ethylhexane-1,6-diyl,4,5-dimethyl-3-ethylhexane-1,6-diyl,2,3-dimethyl-4-ethylhexane-1,6-diyl,2,5-dimethyl-4-ethylhexane-1,6-diyl,3,5-dimethyl-4-ethylhexane-1,6-diyl, 3,4-diethylhexane-1,6-diyl,2-methylheptane-1,7-diyl, 3-methylheptane-1,7-diyl,4-methylheptane-1,7-diyl, 5-methylheptane-1,7-diyl,6-methylheptane-1,7-diyl, 2,3-dimethylheptane-1,7-diyl,2,4-dimethylheptane-1,7-diyl, 2,5-dimethylheptane-1,7-diyl,2,6-dimethylheptane-1,7-diyl, 3,3-dimethylheptane-1,7-diyl,3,4-dimethylheptane-1,7-diyl, 3,5-dimethylheptane-1,7-diyl,3,6-dimethylheptane-1,7-diyl, 4,4-dimethylheptane-1,7-diyl,4,5-dimethylheptane-1,7-diyl, 4,6-dimethylheptane-1,7-dlyl,5,5-dimethylheptane-1,7-diyl, 5,6-dimethylheptane-1,7-diyl,2,3,3-trimethylheptane-1,7-diyl, 2,3,4-trimethylheptane-1,7-diyl,2,3,5-trimethylheptane-1,7-diyl, 2,3,6-trimethylheptane-1,7-diyl,2,4,4-trimethylheptane-1,7-diyl, 2,4,5-trimethylheptane-1,7-diyl,2,4,6-trimethylheptane-1,7-diyl, 2,5,5-trimethylheptane-1,7-diyl,2,5,6-trimethylheptane-1,7-diyl, 3,3,4-trimethylheptane-1,7-diyl,3,3,5-trimethylheptane-1,7-diyl, 3,3,6-trimethylheptane-1,7-diyl,3,4,4-trimethylheptane-1,7-diyl, 3,4,5-trimethylheptane-1,7-diyl,3,4,6-trimethylheptane-1,7-diyl, 3,5,5-trimethylheptane-1,7-diyl,3,5,6-trimethylheptane-1,7-diyl, 4,4,5-trimethylheptane-1,7-diyl,4,4,6-trimethylheptane-1,7-diyl, 4,5,5-trimethylheptane-1,7-diyl,4,5,6-trimethylheptane-1,7-diyl, 3-ethylheptane-1,7-diyl,4-ethylheptane-1,7-diyl, 5-ethylheptane-1,7-diyl,3-ethyl-2-methylheptane-1,7-diyl, 3-ethyl-4-methylheptane-1,7-diyl,3-ethyl-5-methylheptane-1,7-diyl, 3-ethyl-6-methylheptane-1,7-diyl,4-ethyl-2-methylheptane-1,7-diyl, 4-ethyl-3-methylheptane-1,7-diyl,4-ethyl-4-methylheptane-1,7-diyl, 4-ethyl-5-methylheptane-1,7-diyl,4-ethyl-6-methylheptane-1,7-diyl, 5-ethyl-2-methylheptane-1,7-diyl,5-ethyl-3-methylheptane-1,7-diyl, 5-ethyl-4-methylheptane-1,7-diyl,5-ethyl-5-methylheptane-1,7-diyl, 5-ethyl-6-methylheptane-1,7-diyl,4-n-propylheptane-1,7-diyl, 4-i-propylheptane-1,7-diyl,2-methyloctane-1,8-diyl, 3-methyloctane-1,8-diyl,3-methyloctane-1,8-dlyl, 4-methyloctane-1,8-diyl,5-methyloctane-1,8-diyl, 6-methyloctane-1,8-diyl,7-methyloctane-1,8-diyl, 2,3-dimethyloctane-1,8-diyl,2,4-dimethyloctane-1,8-diyl, 2,5-dimethyloctane-1,8-diyl,2,6-dimethyloctane-1,8-diyl, 2,7-dimethyloctane-1,8-diyl,3,3-dimethyloctane-1,8-diyl, 3,4-dimethyloctane-1,8-diyl,3,5-dimethyloctane-1,8-diyl, 3,6-dimethyloctane-1,8-diyl,3,7-dimethyloctane-1,8-diyl, 4,4-dimethyloctane-1,8-diyl,4,5-dimethyloctane-1,8-diyl, 4,6-dimethyloctane-1,8-diyl,4,7-dimethyloctane-1,8-diyl, 5,5-dimethyloctane-1,8-diyl,5,6-dimethyloctane-1,8-diyl, 5,7-dimethyloctane-1,8-diyl,6,6-dimethyloctane-1,8-diyl, 6,7-dimethyloctane-1,8-diyl,3-ethyloctane-1,8-diyl, 4-ethyloctane-1,8-diyl, 5-ethyloctane-1,8-diyl,6-ethyloctane-1,8-diyl, 2-methylnonane-1,9-diyl,3-methylnonane-1,9-diyl, 4-methylnonane-1,9-diyl,5-methylnonane-1,9-diyl, 6-methylnonane-1,9-diyl,7-methylnonane-1,9-diyl and 8-methylnonane-1,9-diyl. Of these alkylenes,straight chain alkylenes are preferred, and they are ethane-1,2-diyl,propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl,heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, anddecane-1,10-diyl. More preferred are ethane-1,2-diyl, propane-1,3-diyl,and butane-1,4-diyl. Even more preferred is ethane-1,2-diyl.

[0032] Some of the foregoing alkylene groups include those containing anasymmetric carbon atom. The configuration with respect to the asymmetriccarbon atom may be R-configuration or S-configuration in the presentinvention.

[0033] As R₁ in SO₃R₁ as R, a hydrogen atom, a methyl group, an ethylgroup, an n-propyl group, and an i-propyl group can be named. Of them,hydrogen and i-propyl are preferred.

[0034] As R₂ in COOR₂ as R, a hydrogen atom, a methyl group, an ethylgroup, an n-propyl group, and an i-propyl group can be named. Of them,hydrogen and methyl are particularly preferred.

[0035] Examples of the R are a sulfoxyl group, a methoxysulfonyl group,an ethoxysulfonyl group, an n-propoxysulfonyl group, ani-propoxysulfonyl group, a carboxyl group, a methoxycarbonyl group, anethoxycarbonyl group, an n-propoxycarbonyl group, and ani-propoxycarbonyl group. Of them, a sulf oxyl group, ani-propoxysulfonyl group, a carboxyl group, and a methoxycarbonyl groupare preferred, and a carboxyl group, and a methoxycarbonyl group arefurther preferred.

[0036] Typically, preferred examples of AR include an ethane-1,2-diylgroup terminally substituted by a sulfoxyl group, an i-propoxysulfonylgroup, a carboxyl group or a methoxycarbonyl group, a propane-1,3-diylgroup terminally substituted by a sulfoxyl group, an i-propoxysulfonylgroup, a carboxyl group or a methoxycarbonyl group, a butane-1,4-diylgroup terminally substituted by a sulfoxyl group, an i-propoxysulfonylgroup, a carboxyl group or a methoxycarbonyl group, a pentane-1,5-dlylgroup terminally substituted by a sulfoxyl group, an i-propoxysulfonylgroup, a carboxyl group or a methoxycarbonyl group, a hexane-1,6-diylgroup terminally substituted by a sulfoxyl group, an i-propoxysulfonylgroup, a carboxyl group or a methoxycarbonyl group, a heptane-1,7-diylgroup terminally substituted by a sulfoxyl group, an i-propoxysulfonylgroup, a carboxyl group or a methoxycarbonyl group, an octane-1,8-diylgroup terminally substituted by a sulfoxyl group, an i-propoxysulfonylgroup, a carboxyl group or a methoxycarbonyl group, a nonane-1,9-diylgroup terminally substituted by a sulfoxyl group, an i-propoxysulfonylgroup, a carboxyl group or a methoxycarbonyl group, and adecane-1,10-diyl group terminally substituted by a sulfoxyl group, ani-propoxysulfonyl group, a carboxyl group or a methoxycarbonyl group. Ofthem, a 2-carboxyethyl group, a 2-methoxycarbonylethyl group, a3-carboxypropyl group, a 3-methoxycarbonylpropyl group, a 4-carboxybutylgroup and a 4-methoxycarbonylbutyl group are particularly preferred, anda 2-carboxyethyl group and a 2-methoxycarbonylethyl group are furtherpreferred.

[0037] As the vitamin D derivative of the general formula (I),2β-(2-carboxyethyloxy)-1α,3β,25-trihydroxycholesta-5,7-10(19)-triene,and2β-(2-methoxycarbonylethyloxy)-1α,3β,25-trihydroxycholesta-5,7-10(19)-trieneare preferred.

[0038] In the definition of the steroid compound of the general formula(II), A is defined as defined in the general formula (I). Examples ofthe preferred groups, particularly preferred groups, and furtherpreferred groups, as A, are the same as those for the A in the generalformula (I).

[0039] As X, a chlorine atom, a bromine atom, and an iodine atom arecited. Of them, an iodine atom is preferred.

[0040] The hydroxyl group protecting groups in R_(a), R_(b) and R_(c)include, for example, acyl groups such as formyl, acetyl, propionyl,butyryl, isobutyryl, valeryl, isovaleryl, pivaloyl, caproyl,trifluoroacetyl and benzoyl; alkoxycarbonyl groups such asmethoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl,allyloxycarbonyl, benzyloxycarbonyl and phenoxycarbonyl; substitutedsilyl groups such as trimethylsilyl, triethylsilyl, triisopropylsilyl,dimethylisopropylsilyl, diethylisopropylsilyl, dimethylthexylsilyl,t-butyldimethylsilyl, t-butyldiphenylsilyl, tribenzylsilyl,tri-p-xylylsilyl, triphenylsilyl, diphenylmethylsilyl andt-butylmethoxyphenylsilyl; substituted methyl groups such asmethoxymethyl, methoxyethoxymethyl, methylthiomethyl, t-butylthiomethyl,β-trichloroethyloxymethyl, trimethylsilylethoxymethyl,p-methoxybenzyloxymethyl and p-chlorobenzyloxymethyl; 2-oxacycloalkylgroups such as tetrahydrofuralyl, and tetrahydropyranyl; and aralkylgroups such as benzyl. Of them, substituted silyl groups such astrimethylsilyl, triethylsilyl, triisopropylsilyl,dimethylisopropylsilyl, diethylisopropylsilyl, dimethylthexylsilyl,t-butyldimethylsilyl, t-butyldiphenylsilyl, tribenzylsilyl,tri-p-xylylsilyl, triphenylsilyl, diphenylmethylsilyl andt-butylmethoxyphenylsilyl are preferred. Further, triethylsilyl andt-butyldimethylsilyl are particularly preferred, and triethylsilyl isevenmore preferred. The R_(a), R_(b) and R_(c) may be the same ordifferent, but are preferably the same.

[0041] As the dienophile capable of protecting conjugated double bondsin the definition of R_(p), R_(g), R_(y) and R_(z),4-phenyl-1,2,4-triazoline-3,5-dione (PTAD), dimethyl maleate and diethylmaleate are preferred, and 4-phenyl-1,2,4-triazoline-3,5-dione isparticularly preferred.

[0042] As the steroid compound of the general formula (II), a PTADadduct of2β-(2-iodoethyloxy)-1α,3β,25-tris(triethylsilyloxy)cholesta-5,7-diene ispreferred.

[0043] The vitamin D derivative of the general formula (I) according tothe invention is a novel compound, and can be synthesized, for example,by using 2β-(2-hydroxyethyloxy)-1α,3β,25-trihydroxycholesta-5,7-diene(compound 1) as a starting material which is described in JapanesePatent Publication No. 1994-23185 (the contents of this publication areall incorporated herein by reference) and performing a methodexemplified by the following reaction scheme with the use of desiredreagents, where necessary:

[0044] In synthesizing compound 1, instead of ethane-1,2-diol, there maybe used a straight chain alkane substituted at both terminal positionsby hydroxyl groups which is propane-1,3-diol, butane-1,4-diol,pentane-1,5-diol, hexane-1,6-diol, heptane-1,7-diol, octane-1,8-diol,nonane-1,9-diol or decane-1,10-diol, or a C₃₋₁₀ branched chain alkanehaving a main chain substituted at both terminal positions by hydroxylgroups. The use of such a compound makes it possible to obtain astarting material in which the. 2-hydroxyethyloxy group at the2β-position of compound 1 has been converted to a straight chain alkoxygroup terminally substituted by a hydroxyl group, i.e.,3-hydroxypropoxy, 4-hydroxybutyloxy, 5-hydroxypentyloxy,6-hydroxyhexyloxy, 7-hydroxyheptyloxy, 8-hydroxyoctyloxy,9-hydroxynonyloxy or 10-hydroxydecyloxy, or a C₃₋₁₀ branched chainalkoxy group having a main chain terminally substituted by a hydroxylgroup.

[0045] Alternatively, these starting materials can be synthesized bymethods which react epoxide-containing steroid compounds with alcoholsunder basic conditions as described in Japanese Unexamined PatentPublication No. 1994-340690 (the contents of this publication are allincorporated herein by reference).

[0046] Conversion from compound 1 into compound 3 is performed byselectively protecting only the hydroxyl group of the terminalhydroxyalkoxy group at the 2β-position without protecting the hydroxylgroups at the 1α-, 3β- and 25-positions of compound 1. Usable as theprotecting group are all groups that can selectively protect only thehydroxyl group of the terminal hydroxyalkoxy group at the 2β-positionwithout substantially adversely affecting the other portions of themolecule and which ensure that the hydroxyl groups at the 1α-, 3β- and25-positions will not be simultaneously deprotected during deprotection.Of them, an acy group is preferred. Non-limiting examples of the acylgroup are saturated alkylcarbonyl groups such as formyl, acetyl,propionyl, butyryl, isobutyryl, valeryl, isovaleryl, pivaloyl, caproyl,lauroyl, myristoyl, palmitoyl, stearoyl, hydratropoyl,cyclohexanecarbonyl, phenylacetyl and 4-methoxyphenylacetyl; unsaturatedalkylcarbonyl groups such as acryloyl, propioloyl, methacryloyl,crotonoyl, isocrotonoyl, oleoyl, elaidoyl, atropoyl and cinnamoyl; andarylcarbonyl groups such as benzoyl, 4-nitrobenzoyl, 4-chlorobenzoyl,4-methoxybenzoyl, naphthoyl, toluoyl, 3-furoyl, 2-thenoyl, nicotinoyland isonicotinoyl. Of them, acetyl, propionyl and benzoyl are preferred,and acetyl is further preferred. As an acylating agent, there can beused an acyl halide having any of the above-mentioned groups (thehalogen atom of the halide may be chlorine, bromine or iodine), and anacid anhydride having any of the above-mentioned acyl groups. Amongthem, acetyl chloride, acetic anhydride, propionyl chloride and benzoylchloride are preferred, and acetic anhydride is further preferred. Thebase used in the reaction may be an amine such as triethylamine,diisopropylethylamine, pyridine or pyrazine. Preferably, pyridine isused. If desired, a solvent inert to the reaction, such asdichloromethane, may be added. Also, a catalyst for promoting thereaction, such as 4-dimethylaminopyridine (DMAP), may be added, wherenecessary. The reaction temperature may be −20 to 60° C., preferably −10to 10° C. The reaction time may be 0.1 to 36 hours, preferably 1 to 3hours.

[0047] Conversion from compound 3 into compound 4 is performed byprotecting the hydroxyl groups at the 1α-, 3β- and 25-positions ofcompound 3. Usable as the protecting group are all groups that canprotect the hydroxyl groups at the 1α-, 3β- and 25-positions at the sametime, without substantially adversely affecting the other portions ofthe molecule. When the protecting group for the hydroxyl group of theterminal hydroxyalkoxy group at the 2β-position is an acy group, asubstituted silyl group is preferred. Non-limiting examples of thesubstituted silyl group are trimethylsilyl, triethylsilyl,triisopropylsilyl, dimethylisopropylsilyl, diethylisopropylsilyl,dimethylthexylsilyl, t-butyldimethylsilyl, t-butyldiphenylsilyl,tribenzylsilyl, tri-p-xylylsilyl, triphenylsilyl, diphenylmethylsilyl,and t-butylmethoxyphenylsilyl. Of them, triethylsilyl andt-butyldimethylsilyl are preferred, and triethylsilyl is furtherpreferred. The agents for introducing the substituted silyl group may besubstituted silyl halides having the above-mentioned groups (the halogenatom of the halide may be chlorine, bromine or iodine), andtrifluoromethanesulfonates having the above-mentioned substituted silylgroups. Among them, triethylsilyl chloride, t-butyldimethylsilylchloride, triethylsilyl trifluoromethanesulfonate andt-butyldimethylsilyl trifluoromethanesulfonate are preferred, andtriethylsilyl trifluoromethanesulfonate is further preferred. The baseto be used in the reaction may be triethylamine, pyridine, imidazole, or2,6-lutidine. Preferably, imidazole and 2,6-lutidine are used, andfurtherpreferably, 2,6-lutidineisused. If desired, a solvent inert tothe reaction, such as tetrahydrofuran (THF), N,N-dimethylformamide,1,3-dimethyl-2-imidazolidinone (DMI), or dichloromethane, may be added.Also, a catalyst for promoting the reaction, such as1-hydroxybenzotriazole, may be added, where necessary. The reactiontemperature is not restricted, but is generally −10 to 120° C.,preferably −5 to 10° C. The reaction time is not restricted, but isgenerally 1 to 30 hours, preferably 1 to 3 hours.

[0048] Conversion from compound 4 into compound 5 is performed byselectively removing only the hydroxyl group protecting group of theterminal hydroxyalkoxy group at the 2β-position, without removing thehydroxyl group protecting groups at the 1α-, 3β- and 25-positions ofcompound 4. Usable as the method of deprotection are all methods thatcan selectively remove only the hydroxyl group protecting groups of theterminal hydroxyalkoxy group at the 2β-position, without substantiallyadversely affecting the other portions of the molecule and which ensurethat the hydroxyl group protecting groups at the 1α-, 3β- and25-positions will not be simultaneously removed during deprotection.When the hydroxyl group protecting group of the terminal hydroxyalkoxygroup at the 2β-position is an acyl group and if the hydroxyl groupprotecting groups at the 1α-, 3β- and 25-positions are substituted silylgroups, for example, an exemplary applicable method is the hydrolysis ofcompound 4 with a base. As the base, sodium hydroxide, potassiumhydroxide, lithium hydroxide, or barium hydroxide can be used.Preferably, potassiumhydroxide is used. As the reaction solvent, water,methanol, ethanol, propanol, tetrahydrofuran, or a mixture of these maybe used. Preferably, a mixture of methanol and tetrahydrofuran is used.The reaction temperature may be 0 to 75° C., preferably 10 to 35° C. Thereaction time may be 0.5 to 20 hours, preferably 1 to 3 hours. Anotherapplicable example method is by reacting compound 4 with a metal hydridecomplex compound, such as lithium aluminum hydride, for 1 to 5 hours ata temperature of −10 to 50° C. in a solvent inert to the reaction, suchas tetrahydrofuran.

[0049] Conversion from compound 5 into compound 6 is performed byprotecting the 5,7-diene portion of compound 5. The protecting reagentmay be all compounds that can protect the 5,7-diene portion, withoutsubstantially adversely affecting the other portions of the molecule. Ofthem, 4-phenyl-1,2,4-triazoline-3,5-dione, dimethyl maleate and diethylmaleate are preferred, and 4-phenyl-1,2,4-triazoline-3,5-dione isfurther preferred. Usable as the solvents in the reaction are allsolvents that are inert to the reaction and which dissolve both ofcompound 5 and the above-mentioned protecting reagent. A preferredexample of the solvent is dichloromethane. The reaction temperature isnot restricted, but is generally 0 to 50C, preferably 15 to 30° C. Thereaction time is not restricted, either but is generally 0.1 to 20hours, preferably 0.2 to 2 hours.

[0050] Conversion from compound 6 into the steroid compound of thegeneral formula (II), in which R_(q) and R_(y) together form a doublebond between the 6-position and the 7-position, and R_(p) and R_(z) arebound to a dienophile capable of protecting conjugated double bonds(e.g., the steroid compound is compound 7), is performed by reactingcompound 6 with a halogen in the presence of a base and a phosphinecompound to convert the hydroxyl group of the terminal hydroxyalkoxygroup at the 2β-position into a halogen atom. As the base, imidazole orbenzimidazole can be used. Preferably, imidazole is used. The phosphinecompound may be a trialkylphosphine or a triarylphosphine, andpreferably, triphenylphosphine is used. As the halogen, iodine ispreferably used. Usable as the solvents in the reaction are all solventsthat are inert to the reaction and which make the reaction systemhomogeneous. A preferred example of the solvent is dichloromethane. Thereaction temperature may be −5 to 40° C., preferably 15 to 35° C. Thereaction time may be 0.5 to 20 hours, preferably 1 to 3 hours.

[0051] Subjecting compound 7 to conversion of compound 9 into compound10 (to be described later on), or a step having an effect comparable tothis conversion, gives a steroid compound of the general formula (II) inwhich R_(p) and R_(q) together form a double bond between the 5-positionand the 6-position, and R_(y) and R_(z) together form a double bondbetween the 7-position and the 8-position.

[0052] Further, compound 7, or a steroid compound of the general formula(II) in which R_(p) and R_(q) together form a double bond between the5-position and the 6-position, and R_(y) and R_(z) together form adouble bond between the 7-position and the 8-position, is subjected to acustomary reaction for elimination of a protecting group (when R_(a),R_(b) and R_(c) are substituted silyl groups, the preferred method is toreact the compound with a substituted ammonium fluoride, such astetra-n-butylammonium fluoride, for a reaction time of 1 to 20 hours ata reaction temperature of 25 to 120° C. with the use of a solvent suchas tetrahydrofuran, N,N′-dimethylpropyleneurea, or1,3-dimethyl-2-imidazolidinone). By this measure, a steroid compound ofthe general formula (II), in which R_(a), R_(b) and R_(c) are hydrogenatoms, can be obtained. Subjecting this steroid compound to a hydroxylgroup protecting reaction known among people skilled in the art canyield a steroid compound of the general formula (II) in which R_(a),R_(b) and R_(c) are each the aforementioned hydroxyl group protectinggroup, such as an acyl group, an alkoxycarbonyl group, a substitutedsilyl group, a substituted methyl group, a 2-oxacycloalkyl group, or anaralkyl group.

[0053] Conversion from compound 7 into compound 8 is performed byreacting compound 7 with a cyanide compound to convert the halogen atomof the terminal haloalkoxy group at the 2β-position into a cyano group.As the cyanide compound, sodium cyanide or potassium cyanide can beused. Preferably, sodium cyanide is used. The solvent to be used for thereaction may be dimethyl sulfoxide, N,N-dimethylformamide,tetrahydrofuran, or a mixture of these. Preferably, a mixture ofdimethyl sulfoxide and tetrahydrofuran is used. The reaction temperatureis not restricted, but is generally 0 to 90° C., preferably 20 to 60° C.The reaction time is not restricted, but is generally 1 to 36 hours,preferably 2 to 6 hours.

[0054] In the case where the protecting groups of the hydroxyl groups atthe 1α-, 3β- and 25-positions of compound 8 are the substituted silylgroups, conversion from compound 8 into compound 9 is performed byreacting compound 8 with an alcohol solution of a hydrogen halide toconvert the cyano group of the terminal cyanoalkoxy group at the2β-position into an alkoxycarbonyl group and simultaneously remove thegroups protecting the hydroxyl groups at the 1α-, 3β-and 25-positions.As the hydrogen halide, hydrogen chloride orhydrogenbromide can be used.Preferably, hydrogen chloride is used. The alcohol maybe methanol,ethanol, n-propanol, or i-propanol. Preferably, methanol is used. Ifdesired, a solvent inert to the reaction, such as diethyl ether, may beadded. The reaction temperature may be 0 to 80° C., preferably 10 to 30°C. The reaction time may be 0.5 to 30 hours, preferably 2 to 10 hours.

[0055] Conversion from compound 9 into compound 10 is performed byheating compound 9 in a solvent to remove the protecting group for the5,7-diene portion, thereby achieving deprotection. The solvent may bedimethyl sulfoxide, N,N-dimethylformamide, or1,3-dimethyl-2-imidazolidinone. Preferably,1,3-dimethyl-2-imidazolidinone is used. Where necessary, a reagent forpromoting the reaction, such as potassium carbonate, may be added. Thereaction temperature is not restricted, but is generally 80 to 155° C.,preferably 100 to 150° C. The reaction time is not restricted, eitherbut is generally 0.5 to 15 hours, preferably 0.5 to 3 hours.

[0056] Conversion from compound 10 into compound 2 is performed byconverting provitami n D to previtamin D, followed by convertingprevitamin D to vitamin D. Conversion to previtamin D is performed byirradiating provitamin D with ultraviolet rays in a solvent. The solventmay be ethanol, tetrahydrofuran, benzene or toluene, and preferablyethanol or tetrahydrofuran is used. Ultraviolet rays may be naturalultraviolet rays, or artificial ultraviolet rays produced by lamps, etc.Where necessary, ultraviolet light with wavelengths unnecessary for thereaction may be eliminated beforehand with the use of a filter or thelike. The reaction temperature may be −20 to 10° C., preferably −5 to 5°C. The reaction time can be varied, as desired, according to theconcentration of provitamin D. Generally, the reaction time may be 30seconds to 7 days.

[0057] Subsequent conversion to vitamin D is performed by heatingprevitamin D in a solvent. The solvent may be ethanol, tetrahydrofuran,benzene or toluene, and preferably ethanol or tetrahydrofuran is used.The reaction temperature may be 0 to 100° C., preferably 4 to 80° C. Thereaction time can generally range from 30 minutes to 10 days. If thereaction time exceeds 12 hours, the reaction may be performed withshield from light.

[0058] If compound 8 is reacted with a solution of the hydrogen halidein a mixture of alcohol and water when converting compound 8 to compound9, there can be obtained a compound in which the cyano group of theterminal cyanoalkoxy group at the 2β-position of compound 8 has beenconverted to a carboxyl group.

[0059] If this compound, in which the cyano group of the terminalcyanoalkoxy group at the 2β-position of compound 8 has been converted toa carboxyl group, is subjected to the steps of converting compound 9 tocompound 10, and then converting compound 10 to compound 11, or stepscomparable in effect to these steps, a compound of the general formula(I) in which R is COOH can be obtained.

[0060] If, in the conversion from compound 7 to compound 8, compound 7or a compound obtained by removing the protecting group of the 5,7-dieneportion from compound 7 is reacted with a base-treated methanesulfonicacid ester instead of the cyanide compound, there can be obtained acompound in which the cyano group of compound 8 has been converted toSO₃R₃ (wherein R₃ denotes a straight chain or branched chain alkyl groupwith 1 to 3 carbon atoms), or a compound in which the protecting groupfor the 5,7-diene portion has been removed for deprotection. The basemay be n-butyllithium, s-butyllithium, t-butyllithium, phenyllithium, orlithium diisopropylamide, and n-butyllithium and lithiumdiisopropylamide are preferred. The methanesulfonic acid ester may bemethyl methanesulfonate, ethyl methanesulfonate, or i-propylmethanesulfonate. Preferred is i-propyl methanesulfonate. The solventusable in the reaction is all solvents that are inert to the reaction.The preferred solvents are, for example, diethyl ether andtetrahydrofuran. Where necessary, a solvent effective in promoting thereaction, such as N,N′-dimethylpropyleneurea, may be added. The reactiontemperature may be −100 to 0° C., and the reaction time may be 0.5 to 20hours. Deprotection of the protecting group for the 5,7-diene portion ofcompound 7 can be performed in the same manner as in the conversion fromcompound 9 to compound 10.

[0061] Further, the compound, in which the cyano group of compound 8 hasbeen converted to SO₃R₃ (wherein R₃ denotes a straight chain or branchedchain alkyl group with 1 to 3 carbon atoms), is subjected to ahydrolysis reaction under acidic conditions which is well known amongpeople skilled in the art, such as a reaction with a hydrous ethanolsolution of sulfuric acid at a reaction temperature of 0 to 50° C., thisreaction being described in J. Chem. Soc., Perkin Trans. 2, 293-299(1987). This reaction yields a compound in which the cyano group ofcompound 8 has been converted to SO₃H, or a compound having the cyanogroup of compound 8 converted to SO₃H and in which at least one of thehydroxyl group protecting groups at the 1α-, 3β-, and 25-positions ofthe compound has been removed.

[0062] Further, the compound in which the cyano group of compound 8 hasbeen converted to SO₃R₃ (wherein R₃ denotes a straight chain or branchedchain alkyl group with 1 to 3 carbon atoms), a compound in which thecyano group of compound 8 has been converted to SO₃H, or a compoundhaving the cyano group of compound 8 converted to SO₃H and in which atleast one of the hydroxyl group protecting groups at the 1α-, 3β-, and25-positions of the compound has been removed, is subjected, asnecessary, to the step of removing the hydroxyl group protecting groupsat the 1α-, 3β-, and 25-positions (in this step, if the hydroxyl groupprotecting groups at the 1α-, 3β-, and 25-positions are substitutedsilyl groups, the preferred method is to react the compound with asubstituted ammonium fluoride, such as tetra-n-butylammonium fluoride,for a reaction time of 1 to 20 hours at a reaction temperature of 25 to120° C. with the use of a solvent such as tetrahydrofuran,N,N′-dimethylpropyleneurea, or 1,3-dimethyl-2-imidazolidinone), and thento the step of conversion from compound 9 to compound 10, followed bythe step of conversion from compound 10 to compound 11, or to stepscomparable in effect to these steps. This procedure gives a compound ofthe general formula (I) in which R is SO₃R₁ (wherein R₁ denotes ahydrogen atom, or a straight chain or branched chain alkyl group with 1to 3 carbon atoms).

[0063] The compound of the invention can also be produced by applyingthe specific manufacturing methods described in the Examples to beoffered later on.

[0064] The compound of the invention has affinity for a vitamin Dreceptor and a vitamin D-binding protein, and is useful as a drug, forexample, a drug for treatment of diseases due to abnormal calciummetabolism. A pharmaceutical composition containing the compound of theinvention as an active ingredient can be administered orally (byingestion or inhalation) or parenterally (e.g., intravenously,subcutaneously, or topically). For administration, the composition canbe formed into a preparation suitable for the mode of administration.

[0065] The pharmaceutical composition containing the compound of theinvention as the active ingredient can be formed into a preparation byordinary pharmaceutical manufacturing techniques. Depending on itsapplications, it can be used as solid and liquid preparations, such ascapsules, granules, creams, powders, syrups, tablets, injections, andointments.

[0066] In forming such preparations, nontoxic additives usually used inthe pharmaceutical manufacturing of these types of drugs can be used,including stabilizers, lubricants, buffering agents, base materials,flavoring agents, binders, antioxidants, coating agents, colorants,isotonization agents, vehicles, dispersants, disintegrants,preservatives, solvent promoters, and solubilizing agents.

[0067] Examples of the stabilizers are sulfites (sodium hydrogensulfite,sodium sulfite, etc.), edetates (sodium edetate, tetrasodium edetate,etc.), hydrogenated oil, sesame oil, sodium chondroitin sulfate, anddibutylhydroxytoluene.

[0068] Examples of the lubricants are dried aluminum hydroxide gel,glycerin, silicic acid and its salts (light silicic anhydride, magnesiumsilicate, etc.), stearic acid and its salts (aluminum stearate, calciumstearate, magnesium stearate, etc.), talc, polyethylene glycol, andphosphoric acid.

[0069] Examples of the bufferingagents are acetic acid, tartaric acid,sodium carbonate, boric acid, phosphoric acid and its salts (trisodiumphosphate, disodium hydrogenphosphate, dipotassium hydrogenphosphate,etc.).

[0070] Examples of the base materials are glycerin, vegetable oils(olive oil, sesame oil, wheat germ oil, etc.), stearyl alcohol, cetanol,lard, white petrolatum, paraffin, bentonite, lanolin fatty acidisopropyl ester, and petrolatum.

[0071] Examples of the flavoring agents are L-aspartic acid and itssalts (monosodium L-aspartate, magnesium L-aspartate, etc.),saccharinsodium, sugars (lactose, sucrose, glucose, D-mannitol, etc.),dl-menthol, and 1-menthols.

[0072] Examples of the binders are agar, stearyl alcohol, gelatin,cellulose and its derivatives (ethylcellulose,carboxymethylethylcellulose, hydroxypropylcellulose,hydroxypropylmethylcelluloses, etc.), starch and its derivatives(pregelatinized starch, oxidized starch, dextrin, etc.), sugars(lactose, sucrose, microcrystalline cellulose, glucose, etc.),tragacanth, and polyvinyl alcohol.

[0073] Examples of the antioxidants are ascorbic acid, L-ascorbylstearate, sulfites (sodium sulfite, sodium hydrogensulfite, sodiumpyrosulfite, etc.), sodium edetate, erythorbic acid, cysteinehydrochloride, dibutylhydroxytoluene, sodium thiomalate, concentratedmixed tocopherol, butylhydroxyanisole, and propyl gallate.

[0074] Examples of the coating agents are shellac, cellulose derivatives(cellulose acetate, hydroxypropylcellulose, cellulose acetate phthalate,hydroxypropylmethylcelluloses, etc.), polyvinyl pyrrolidones,polyethylene glycol, polyethylene glycol, methacrylic acid copolymers,and liquid paraffin.

[0075] Examples of the colorants are indigocarmine, caramel, andriboflavin.

[0076] Examples of the isotonization agents are potassium chloride,sodium chloride, glycerin, sodium bromide, D-sorbitol, nicotinamide,glucose, and boric acid.

[0077] Examples of the vehicles are silicates (synthetic aluminumsilicate, magnesium aluminosilicate, calcium silicate, magnesiumsilicate, etc.), tartaric acid, potassium hydrogentartrate, magnesiumhydroxide, cellulose and its derivatives (hydroxypropylcellulose,hydroxypropylmethylcellulose, methylcellulose, etc.), starch and itsderivatives (sodium carboxymethyl starch, β-cyclodextrin, dextrin,hydroxypropyl starch, etc.), sugars (lactose, sucrose, glucose,D-mannitol, etc.), glyceryl monostearate, and sorbitan monosLearaLe.

[0078] Examples of the dispersants are acacia, propylene glycolalginate, stearic acid and its salts (zinc stearate, magnesium stearate,etc.), sorbitan sesquioleate, D-sorbitol, tragacanth, methylcellulose,and aluminum monostearate.

[0079] Examples of the disintegrants are agar, gelatin, cellulose andits derivatives (crystalline cellulose, cellulose acetate phthalate,hydroxypropylcellulose, hydroxypropylmethylcellulose, etc.), carbonates(calcium carbonate, sodium hydrogencarbonate, magnesium carbonate,etc.), starch and its derivatives (sodium carboxymethyl starch,hydroxypropyl starch, etc.), and tragacanth.

[0080] Examples of the preservatives are alcohols (chlorobutanol,phenethyl alcohol, propylene glycol, benzyl alcohol, etc.), benzalkoniumchloride, benzethonium chloride, dried sodium sulfite, dried sodiumsulfate, cresol, chlorocresol, dibutylhydroxytoluene, potassium sorbate,sodium dehydroacetate, parahydroxybenzoate esters (isobutylparahydroxybenzoate, ethyl parahydroxybenzoate, methylparahydroxybenzoate, etc.), phenol, formaldehyde, and phosphoric acid.

[0081] Examples of the solvent promoters are sodium benzoate,ethylenediamine, citric acid, sodium citrate, glycerin, sodium acetate,sodium salicylate, sorbitan sesquioleate, nicotinamide, glucose, benzylalcohol, and polyvinylpyrrolidones.

[0082] Examples of the solubilizing agents are hydrated silicon dioxide,stearic acid and its salts (calcium stearate, magnesium stearate, etc.),talc, and absolute ethanol.

[0083] In addition to these additives, drug components can be added.

[0084] The content of the compound of the invention in any of thepreparations varies according to the dosage form of the preparation.Generally, it is desired that the compound be contained in aconcentration of 0.00001 to 10% by weight. The pharmaceuticalcomposition comprising the compound of the invention can be changedwidely according to the type of warm-blooded animals to be treated,including human, the severity of symptoms, diagnosis by the physician,etc. Generally, the content of the compound, as active ingredient, is0.0000001 to 50 μg/kg/day for oral administration, or 0.000000001 to 10μg/kg/day for parenteral administration.

[0085] The above dose can be administered either at a time or in dividedportions once or several times in a day to seven days. The dose can bechanged, as required, according to the severity of symptoms, judgment ofthe physician, etc.

[0086] The contents of the specification of Japanese Patent ApplicationNo. 1998-137361, the application on the basis of which the presentapplication claims priority are to be incorporated in their entirety byreference.

EXAMPLES

[0087] The present invention will be described concretely by way of thefollowing Examples, which in no way limit the invention.

[0088] To show the usefulness of the compounds according to theinvention, tests were conducted for the affinity of typical compounds ofthe invention for a vitamin D receptor and a vitamin D binding protein.The results of the tests are shown in Test Example.

Example 1 2β-(2-acetyloxyethyloxy)-1α,3β,25-trihydroxycholesta-5,7-diene(Compound 3)

[0089] To a dichloromethane (30 ml) solution of compound 1 (306 mg, 643pmol), pyridine (600 pl) and DMAP (10 mg), acetic anhydride (150 μl,1.59 mmol) was added with ice cooling in an argon atmosphere, and themixture was stirred for 1.5 hours at the same temperature. The reactionmixture was poured into dilute hydrochloric acid, extracted withdichloromethane, and washed with a saturated solution of sodiumcarbonate. The organic phase was dried over magnesium sulfate, and thenthe solvent was distilled off under reduced pressure. The resultingresidue was purified by flash column chromatography(ethanol:dichloromethane=0.3:5) to give colorless oily compound 3 (215mg, 65%), and recover compound 1 (105 mg, 34%). The same procedure wasrepeated for the recovered compound 1. The resulting products werecombined to give compound 3 (260 mg, 79%).

[0090]¹H-NMR: δ 0.63 (3H, s), 0.96 (3H, d, J=6.3 Hz), 1.05 (3H, s), 1.12(6H, s), 2.07 (3H, s), 3.64-3.77 (2H, m), 3.84 (1H, brs), 3.89-4.00 (2H,m), 4.17-4.34 (2H, m), 5.33-5.41 (1H, m), 5.70 (1H, brd, J=3.6 Hz);

[0091] IR(neat)cm⁻¹: 3415 (br), 2930, 1740;

[0092] MS(m/z): 518 (M⁺), 87 (100%);

[0093] UVλmax nm: 293, 282, 271.

Example 22β-(2-acetyloxyethyloxy)-1α,3β,25-tris(triethylsilyloxy)cholesta-5,7-diene(Compound 4)

[0094] To a dichloromethane (15 ml) solution of compound 3 (260 mg, 502pmol) obtained in Example 1, and 2,6-lutidine (877 pl, 7.53 mmol),triethylsilyl trifluoromethanesulfonate (1.14 ml, 5.02 mmol) was addedwith ice cooling in an argon atmosphere, and the mixture was stirred for1.5 hours at the same temperature. The reaction mixture was concentratedunder reduced pressure. The resulting residue was purified by flashcolumn chromatography (5% ethyl acetate/hexane) to give colorless oilycompound 4 (327 mg, 76%).

[0095]¹H-NMR: δ 0.52-0.72 (21H, m), 0.88-1.03 (33H, m), 1.18 (6H, s),2.04 (3H, s), 3.58 (1H, brs), 3.63-3.74 (1H, m), 3.75 (1H, brd, J=3.6Hz), 3.94-4.11 (2H, m), 4.21 (2H, t, J=5.0 Hz), 5.28-5.35 (1H, m),5.57-5.62 (1H, m);

[0096] IR(neat)cm⁻¹: 2950, 1750;

[0097] MS(m/z): 860 (M⁺), 87 (100%);

[0098] UVλmax nm: 293, 282, 271.

Example 32β-(2-hydroxyethyloxy)-1α,3β,25-tris(triethylsilyloxy)cholesta-5,7-diene(Compound 5)

[0099] To a THF (5 ml) solution of compound 4 (327 mg, 380 pmol)obtained in Example 2, a methanol (10 ml) solution of potassiumhydroxide (72 mg, 1.29 mmol) was added, and the mixture was stirred inan argon atmosphere for 1.5 hours at 15 to 30° C. To the reactionmixture, acetic acid (150 μl) was added. Then, the resulting mixture waspoured into water, extracted twice with a solvent mixture of ethylacetate and hexane (1:1), and washed with a saturated solution of sodiumcarbonate and a saturated aqueous solution of sodium chloride in thisorder. The organic phase was dried over magnesium sulfate, and then thesolvent was distilled off under reduced pressure. The resulting residuewas purified by flash column chromatography (8% ethyl acetate/hexane) togive colorless oily compound 5 (173 mg, 56%).

[0100]¹H-NMR: δ 0.51-0.71 (21H, m), 0.89-1.07 (33H, m), 1.19 (6H, s),3.48-3.71 (4H,m), 3.76 (1H, brd, J=3.6 Hz), 3.82-3.91 (1H, m), 4.02-4.13(1H, m), 5.30-5.36 (1H, m), 5.6 (1H, brd, J=5.6 Hz);

[0101] IR(neat)cm : 3465(br), 2955;

[0102] MS(m/z): 818(M⁺), 75 (100%);

[0103] UVλmax nm: 293, 282, 271.

Example 4 PTAD Adduct of2β-(2-hydroxyethyloxy)-1α,3β,25-tris(triethylsilyloxy)cholesta-5,7-diene(Compound 6)

[0104] To a dichloromethane (15 ml) solution of compound 5 (173 mg, 211μmol) obtained in Example 3, a dichloromethane (5 ml) solution of PTAD(37 mg, 211 μmol) was added until the reaction mixture turned red, andthe mixture was stirred for 30 minutes at 15 to 30° C. The reactionmixture was concentrated under reduced pressure, and the residue waspurified by preparative thin-layer chromatography (preparative TLC; 25%ethyl acetate/hexane) to give pale yellow, oily compound 6 (173 mg,82%).

[0105]¹H-NMR: δ 0.51-0.82 (21H, m), 0.89-1.01 (30H, m), 1.05 (3H, s),1.19 (6H, s), 3.00 (1H, dd, J=13.9, 4.6 Hz), 3.58-3.71 (4H, m),3.83-3.89 (2H, m), 3.91(1H, brd, J=3.0 Hz), 4.90-4.99 (1H, m), 6.23 (1H,d, J=8.3 Hz), 6.36 (1H, d, J=8.3 Hz), 7.23-7.49 (5H, m);

[0106] IR(neat)cm⁻¹: 3580 (br), 2950, 1750, 1695;

[0107] MS(m/z): 818 (M⁺-PTAD), 103(100%);

[0108] UVλmax nm: 258, 218, 206.

Example 5 PTAD Adduct of 2β-(2-iodoethyloxy)-1α,3β,25-tris(triethylsilyloxy)cholesta-5,7-diene (Compound 7)

[0109] To a dichloromethane (6.7 ml) solution of compound 6 (173 mg, 174μmol) obtained in Example 4, triphenylphosphine (123 mg, 469 μmol) andimidazole (32 mg, 470 μmol), iodine (75.2 mg, 296 μmol) was added, andthe mixture was stirred in an argon atmosphere for 80 minutes at 15 to30° C. The reaction mixture was poured into a 10% solution of sodiumthiosulfate, and extracted twice with dichloromethane. The organic phasewas dried over magnesium sulfate, and then the solvent was distilled offunder reduced pressure. The residue was purified by preparative TLC (10%ethyl acetate/hexane) to give colorless oily compound 7 (188 mg, 98%).

[0110]¹H-NMR: δ 0.52-0.73 (18H, m), 0.81 (3H, s), 0.88-1.01 (30H, m),1.07 (3H, s), 1.19 (6H, s), 2.97 (1H, dd, J=13.9, 4.6 Hz), 3.20-3.34(2H, m), 3.66 (1H, brt, J=3.3 Hz), 3.69-3.81 (1H, m), 3.97 (1H, brd,J=3.3 Hz), 4.11-4.22 (1H, m), 4.86-4.96 (1H, m), 6.23 (1H, d, J=8.3 Hz),6.35 (1H, d, J-8.3 Hz), 7.22-7.49 (5H, m);

[0111] IR(neat)cm⁻¹: 2980, 1765, 1715;

[0112] MS(m/z): 928 (M⁺-PTAD), 75 (100%);

[0113] UVλmax nm: 256, 204.

Example 6 PTAD Adduct of2β-(2-cyanoethyloxy)-1α,3β,25-tris(triethylsilyloxy)cholesta-5,7-diene(Compound 8)

[0114] To a solution, in dimethyl sulfoxide (26 ml) and THF (15 ml), ofcompound 7 (180 mg, 163 μmol) obtained in Example 5, a dimethylsulfoxide (8 ml) solution of sodium cyanide (8.0 mg, 163 μmol) wasadded, and the mixture was stirred in an argon atmosphere for 3.5 hoursat 50° C. The reaction mixture was poured into ice water, extractedtwice with a solvent mixture of ethyl acetate and hexane (10:1), andwashed once with water. The organic phase was dried over magnesiumsulfate, and then the solvents were distilled off under reducedpressure. The residue was purified by preparative TLC (15% ethylacetate/hexane) to give colorless oily compound 8 (141 mg, 87%).

[0115]¹H-NMR: δ 0.51-0.75 (18H, m), 0.80 (3H, s), 0.89-1.02 (30H, m),1.05 (3H, s), 1.19 (6H, s), 2.98 (1H, dd, J=13.9, 4.6 Hz), 3.66 (1H,brt, J=3.3 Hz), 3.71-3,79 (1H, m), 3.93(1H, brd, J=3.0 Hz), 4.06-4.13(1H, m), 4.90-4.98 (1H, m), 6.23 (1H, d, J=8.3 Hz), 6.35 (1H, d, J=8.3Hz), 7.22-7.49 (5H, m);

[0116] IR(neat)cm⁻¹: 2955, 2250, 1750, 1700;

[0117] MS(m/z): 827 (M⁺-PTAD), 75 (100%);

[0118] UVAλmax nm: 258, 204.

Example 7 PTAD Adduct of2β-(2-methoxycarbonylethyloxy)-1α,3β,25-trihydroxycholesta-5,7-diene(Compound 9)

[0119] To a diethyl ether (6.6 ml) solution of compound 8 (75 mg, 74.9pmol) obtained in Example 6, a methanol solution of hydrogen chloridegas (3.3 ml, corresponding to 735 mg of hydrogen chloride) was added,and the mixture was stirred in an argon atmosphere for 6.5 hours at 15to 30° C. The reaction mixture was concentrated under reduced pressure,and the residue was purified by preparative TLC (ethanol:dichloromethane=1:10) to give colorless oily compound 9 (13 mg, 25%).

[0120]¹H-NMR: δ 0.80 (3H, s), 0.96 (3H, d, J=6.3 Hz), 1.00 (3H, s), 1.21(6H, s), 2.59 (2H, t, J=5.6 Hz), 3.08-3.18 (1H, m), 3.70 (3H, s),3.78-3.98 (4H, m), 4.68-4.78 (1H, m), 6.20 (1H, d, J=8.3 Hz), 6.40 (1H,d, J=8.3 Hz), 7.25-7.42 (5H, m);

[0121] IR(neat)cm⁻¹: 3445 (br), 2950, 1740, 1690;

[0122] MS(m/z): 518 (M⁺-PTAD), 60 (100%).

Example 82β-(2-methoxycarbonylethyloxy)-1α,3β,25-trihydroxycholesta-5,7-diene(Compound 10)

[0123] A DMI (3 ml) solution of compound 9 (18 mg, 26.0 μmol) obtainedin Example 7 was stirred in an argon atmosphere for 1 hour at 140° C.The reaction mixture was left to cool, and then poured into water. Themixture was extracted twice with a solvent mixture of ethyl acetate andhexane (4:1), and washed with water twice. The organic phase was driedover magnesium sulfate, and then the solvents were distilled off underreduced pressure. The residue was purified by preparative TLC (1%ethanol/ethyl acetate) to give white powdery compound 10 (8 mg, 59%).

[0124]¹H-NMR: δ 0.63 (3H, s), 0.96 (3H, d, J=6.6 Hz). 1.00 (3H, s), 1.20(6H, s), 2.61 (2H, t, J=5.8 Hz), 3.64-3.85 (4H, m), 3.74 (3H, s),3.90-4.01 (1H, m), 5.31-5.39 (1H, m), 5.62-5.69 (1H, m);

[0125] IR(KBr)cm⁻¹: 3420 (br), 2960, 1725;

[0126] MS(m/z): 518 (M⁺), 60 (100%);

[0127] UVλmax nm: 294, 282, 271.

Example 92β-(2-methoxycarbonylethyloxy)-1α,3β,25-trihydroxy-9,10-secocholesta-5,7,10(19)-triene(Compound 2)

[0128] An ethanol (200 ml) solution of compound 10 (8 mg, 15.4 μmol)obtained in Example 8 was irradiated with light for 95 seconds with theuse of a 400 W high pressure mercury lamp-Vycor filter, with ice coolingand under bubbling with an argon gas. Then, the irradiated solution washeated under ref lux for 2 hours. The solvent was distilled off underreduced pressure, and the residue was purified by preparative TLC (1%ethanol/ethyl acetate) to give white foamy compound 2 (2 mg, 25%).

[0129]¹H-NMR: δ 0.55 (3H, s), 0.93 (3H, d, J=6.3 Hz), 1.22 (6H, s), 2.66(2H, t, J=5.1 Hz), 3.26 (1H, dd, J-9.1, 2.8 Hz), 3.73 (3H, s), 3.74-3.83(1H, m), 3.92-4.02 (1H, m), 4.24-4.32 (2H, m), 5.08 (1H, s), 5.53 (1H,s), 6.06 (1H, d, J=11.4 Hz), 6.36 (1H, d, J=11.4 Hz);

[0130] IR(neat)cm⁻¹: 3460 (br), 2925, 1735;

[0131] MS(m/z): 518 (M⁺), 60 (100%);

[0132] UVλmax nm: 264, min nm: 229.

Test Example

[0133] Compound 2 of the present invention was evaluated for affinityfor a chick small intestine vitamin D receptor and a rat plasma vitaminD binding protein in comparison with 1α,25-dihydroxyvitamin D₃ or25-hydroxyvitamin D₃.

[0134] Specifically, a ³H-1α,25-dihydroxyvitamin D₃ solution (to testaffinity for a chick small intestine vitamin D receptor) or a³H-25-hydroxyvitamin D₃ solution (to test affinity for a rat plasmavitamin D binding protein) was mixed with a solution of a test compound(1α,25-dihydroxyvitamin D₃, 25-hydroxyvitamin D₃, or compound 2) atvarious-concentrations. A solution of a chick small intestine vitamin Dreceptor, or a solution of a rat plasma vitamin D binding protein wasadded, and the resulting mixture was left to stand. Then, a dextrancoated charcoal solution was added, and the mixture was left to stand inice cooling, and centrifuged. To the supernatant, a liquid scintillatorwas added, and the mixture was measured for radioactivity. B/B₀ (B=thevalue of radioactivity measured upon addition of the test compound,B₀=the value of radioactivity measured without addition of the testcompound) was calculated to find the concentration of the test compoundat which B/B₀=0.5. The results are shown in Tables 1 and 2. TABLE 1Comparative Experiments on Affinity of Vitamin D Derivatives for ChickSmall Intestine Vitamin D Receptor 1,25-Dihydroxyvitamin D₃ Compound 250% binding 0.046 0.455 ability (ng) Ratio 1 1/9.9

[0135] TABLE 2 Comparative Experiments on Affinity of Vitamin DDerivatives for rat plasma vitamin D binding protein 25-Hydroxy-1,25-Dihydroxy- vitamin D₃ vitamin D₃ Compound 2 50% binding 0.209 27 4ability (ng) Ratio 129  1 1/6.8

[0136] As shown in Tables 1 and 2, the compound of the present inventionhas affinity for a vitamin D receptor and a vitamin D binding protein.

[0137] Industrial Applicability

[0138] The compound of the present invention has affinity for a vitaminD receptor and a vitamin D binding protein, and is useful as a drug, forexample, a drug for treatment of diseases due to abnormal calciummetabolism. The compound is considered to be a metabolite of a vitamin Dderivative having a substituent at the 2β-position, especially,2β-(3-hydroxypropoxy)-1α,25-dihydroxyvitamin D₃. This compound canadvantageously be used as an authentic sample to identify thederivative.

What is claimed is:
 1. A steroid compound of the general formula (II)

wherein A denotes a straight chain or branched chain alkylene group with2 to 10 carbon atoms; X denotes a halogen atom; R_(a), R_(b) and R_(c)denote, independently of each other, a hydrogen atom or a hydroxyl groupprotecting group; and R_(p), R_(q), R_(y) and R_(z) are such that R_(p)and R_(q) together form a double bond between the 5-position and the6-position and R_(y) and R_(z) together form a double bond between the7-position and the 8-position or R_(q) and R_(y) together form a doublebond between the 6-position and the 7-position and R_(p) and R_(z) arebound to a dienophile capable of protecting conjugated double bonds. 2.A steroid compound as claimed in claim 1, wherein A is a straight chainalkylene group with 2 to 10 carbon atoms; and X is an iodine atom.